Software-defined networking (SDN) is an approach to networking in which control is decoupled from hardware and given to a software application, referred to herein as a SDN controller. Conventionally, when a packet arrives at a network device in a typical network, the control plane, which is based on the switch's proprietary firmware, tells the device where to forward the packet. In some network devices, the control plane may be configured to recognize different types of packets and treat them differently, such as forwarding the packets to different network devices or dropping the packets if certain criteria are met.
In a SDN enabled network, a network administrator can change how the network devices route data packets using a software application without having to, for example, send a technician to the individual network devices. The administrator can remotely reconfigure the rules in the control plane of the network devices—e.g., prioritizing, de-prioritizing or even blocking specific types of packets—using the SDN controller. A SDN enabled network may allow the administrator to manage traffic loads in a flexible and more efficient manner relative to conventional network devices that use control planes based on firmware.
Moreover, SDN allows a network administrator to configure a switching fabric across multi-vendor hardware and different proprietary firmware. One standard that permits a network administrator to remotely configure and control the control plane of network devices is the OpenFlow® standard (OpenFlow is a trademark of the Open Networking Foundation). Generally, OpenFlow lets network administrators control routing tables for a plurality of network devices using a single SDN controller.
To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements disclosed in one embodiment may be beneficially utilized on other embodiments without specific recitation.